Was told compression good. Leak down not mentioned nor did I ask as I plan to go to the shop later this week to retrieve items from boat and will have more detailed conversations.

Did they put the stethoscope on the oil pan to see if the sound is more prevalent there? Wondering if the windage tray could have shaken loose and getting hit by the crank.

A friend of mine had a noise develop that sounded a little like a lifter ticking. After checking out the top end he finally pulled the motor and tore it down. Turned out that he had hammered out a rod bearing flat as a penny on a railroad track, and it had smashed out and was contacting the main journal webbing. This was on a boosted application.

Not sure where all they put the scope. Will find out more later this week or weekend. Owner said best they can tell it is internal, starboard rear, and not anything they can say they have heard before (i.e. lifter, rod, etc.). Carries good oil pressure as always and oil is clean (only has 15 hours on it). I asked if he took the filter off and cut it open and he said no. Been too soon to send out an oil analysis. At this point, unless removing the valve cover shows something obvious, whether it is internal or at the back of the engine the engine has to come out.

Before taking it to the shop I was able to see the snout on the coupler spinning and didn't see any obvious wobble. I was also able to feel the bolts on the coupler flange. I tried bumping motor over a few times to feel each bolt (no way to know if I got them all) and didn't feel any that were pulled away from flange. To me, it sounded like something hitting the flywheel cover. Again, the weirdest thing is the boat was ran on a Sunday for about an hour and it ran flawless. The following Wednesday it was idled for a few minutes from my slip to the trailer and again, ran great and no noise. Shut her down, take her 20 miles on the trailer, splash her back in the water and death noise. Maybe it is a good thing if it is internal as I had went out on the lake instead of going to the trailer it may have manifested into a really expensive problem if something broke and took out additional items. Probably wouldn't have heard it at speed with wind and exhaust noise.

Reverted water either on shut down pulling onto trailer or when boat was backed into the water after getting gas (my money here). Evidence of water (rust) in all even-bank cylinders but #6 was the lucky one to have enough water to bend the rod. Odd-bank cylinders spotless (no evidence of water/rust). Exhaust manifold/riser pressure tested good. Oil was clear. Y-pipe and tailpipe flappers are prime suspects but I don't have access to boat at the moment.

Spend a little more and put forged slugs and good rods in it. Might as well while it is down.

looks like it took in quite a bit of water.i am to lazy to go back through the thread.what engine and what exhaust.also does it have silent choice?sorry to see that it was not something simple and cheep to fix.

Ouch! Thanks for the update.

496 MAG, Corsa Captains Call, side exit with internal stainless flappers in the tips.

Or starboard side leaned over making your water line higher on that side inwhich reverted water with side exit exhaust. I would measure to make sure you have enough riser height to prevent water reversion.

Boat didn't lean. Engine has 400 + hours. Riser height problems would have shown their face years ago one would think. Builder thinks it has had water pushed up a few times and this time I got unlucky. The last few years the boat only gets taken off and put on the trailer once or twice a year. Otherwise it sits on the lift at the lake. My money is on the y-pipe flapper on the starboard side. That is the most direct route for water to be reverted back up into the engine. And not that it would prevent water from entering, but I did not have the exhaust open when loading or unloading. Hopefully we find a smoking gun and not everything in place.

Engine bored .030 over, new SRP forged slugs and Scat H-beam rods will be installed in all 8 holes.